Steven Soderbergh’s “Traffic” is a searing indictment of the so-called “War on Drugs” — a war which, the film says, cannot be won. It’s not a very cheerful prospect, to be sure, and the film’s insistence on keeping us at arm’s length from the characters’ emotions prevents it from being truly great, though the thought-provoking narrative makes it a pretty electrifying experience nonetheless.

Three concurrent storylines are presented, each intriguing and each some way related to the others. Ostensibly the main character is Robert Wakefield (Michael Douglas, finally allowing himself to look middle-aged and fatherly in a rich-guy sort of way), an Ohio judge recently appointed as the U.S. drug czar. His credibility is jeopardized somewhat by his daughter Caroline’s (Erika Christensen) addiction to an array of drugs, which she does with her fellow upper-class private-school snobs (including one played with amusing know-it-all rebelliousness by Topher Grace from TV’s “That ’70s Show”).

Meanwhile, Mexican police Javier (Benicio Del Toro) and Manolo (Jacob Vargas) are drifting somewhere between mild unethical behavior and outright corruption. (Purely honest law enforcement seems to be a myth in Mexico.) They become involved with Gen. Salazar (Tomas Milian), Mexico’s new equivalent of a “drug czar,” who is intent on destroying the ObregÃ³n cartel that runs drugs through Tijuana and into the states. The competing cartel, Juarez, wants the same thing, and Javier — basically an honest man caught in the middle of some very desperate circumstances — tries to play all sides equally.

More meanwhile, San Diego socialite Helena Ayala (Catherine Zeta-Jones) is suffering embarrassment and financial ruin after her successful businessman-husband Carlos (Steven Bauer) is arrested for drug trafficking. He was fingered by Eduardo Ruiz (Miguel Ferrer), who ratted him out as a means of saving himself when DEA agents Montel Gordon (Don Cheadle) and Ray Castro (Luis Guzman) nailed him in a bust. With Ruiz as the only one who can send Carlos Ayala to prison, it falls on Mrs. Ayala to do what she can to stop him, and the DEA guys have him in protective custody just in case.

The characters from the three stories interact occasionally, making the film come together as a whole literally while the theme unites everything figuratively. Wakefield meets Gen. Salazar; Helena Ayala consults with Mexican drug lords; a Mexican assassin is brought into the states to do some dirty work.

It’s an ambitious film with some elements of true greatness. Its massive scope and gray-area “heroes” lend it respectability, as does the fact that all the scenes in Mexico are in Spanish with English subtitles.

It’s full of real events and real situations — but, unfortunately, no real characters. Michael Douglas’s character should be the example of how drugs affect individuals, but his behavior seems rote.

His wife, Catherine Zeta-Jones (who shares not one second of screen time with her real-life spouse, by the way), plays a character in much the same boat. Helena Ayala is in dire straits, and we get some sense of her frustration, but precious little of her emotions. Everything is dehumanized. It could be argued that dehumanization is the effect of drugs (and, indeed, of the “War on Drugs”), but that doesn’t help “Traffic” seem any more engaging. As it stands, one is interested to know how things will turn out, but one is rarely put in suspense over the fates of the characters or their predicaments.